Heat Exchangers, Methods of Using the Same, and Water Treatment Systems Containing Such Heat Exchangers

A heat exchanger comprising:

• (a) a heat exchanger cartridge comprising:
• a first end comprising a water inlet and a water outlet;
• a second closed end opposite the first end;
• a plurality of tubes bundled together in a cylindrical pattern that extend between the first end and the second end;
• and
• a plurality of baffles in which each baffle is attached to one or more of the plurality of tubes, the plurality of baffles spaced apart along a length of the plurality of tubes;
• and
• (b) a heat exchanger shell comprising:
• a hollow body comprising a first end having an opening for receiving the heat exchanger cartridge, and a second closed end opposite the first end;
• a hypochlorite inlet positioned at the first end of the hollow body;
• and
• a hypochlorite outlet positioned at the second end of the hollow body,
• wherein the plurality of tubes each independently have a length within a range of from 37 and 80 inches, and an inner diameter within a range of from 0.170 inches and 0.190 inches.